package com.itheima.reggie.controller;

import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

@RestController
@RequestMapping("/common")
@Slf4j
public class CommonController {
    //file临时文件暂存位置
    @Value("${reggie.path}")
    private String basePath;

    /**
     * 文件上传
     * @return 需要给客户端返回文件名称，客户端发送保存请求时保存到数据库
     */
    @PostMapping("/upload")
    public R<String> upload(MultipartFile file) {
        log.info(file.toString());
        //file临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除
        String originalFilename = file.getOriginalFilename();

        //截取文件后缀
        assert originalFilename != null;
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));
        //使用uuid重新生成文件名，防止文件名重复造成的文件覆盖
        String fileName = UUID.randomUUID() + suffix;
        //创建一个目录对象
        File dir = new File(basePath);
        //判断当前目录是否存在
        if (!dir.exists()){
            //不存在，创建
            dir.mkdirs();
        }
        try {
            file.transferTo(new File(basePath+fileName));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return R.success(fileName);
    }

    /**
     * 文件下载
     * @param name
     * @param response
     */
    @GetMapping("/download")
    public void download(String name, HttpServletResponse  response){
        try {
            //输入流，通过输入流读取文件内容
            FileInputStream fileInputStream = new FileInputStream(new File(basePath + name));
            //输出流，通过输出流将文件写回浏览器，在浏览器显示图片
            ServletOutputStream outputStream = response.getOutputStream();

            //设置响应的文件类型
            response.setContentType("image/jpeg");

            int len = 0;
            byte[] bytes = new byte[1024];
            while ((len=fileInputStream.read(bytes))!=-1){
                outputStream.write(bytes,0,len);
                outputStream.flush();
            }
            //关闭资源
            outputStream.close();
            fileInputStream.close();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}
